The Tricks of the Trade weblog has a fantastic tip for leaving a voicemail message:

It's considerate to provide your number or other contact information at the beginning of the message, rather than at the end. That way, if the person wasn't able to get the info written down or memorized on the first pass, they don't have to re-listen to the entire message to hear it a second listen.

Can I get an Alleluia? Long VM's with the crucial information buried at the end could lead a person down the road to hari-kari, especially when you come from a very, um, verbose Italian family. (Love you Mom!)